I made one and I drilled the holes too big. The mother squeezed through. My next try was to buy a net-based breeder. The plastic parts that held the net from collapsing were a death trap for the fry. They would go between the hard plastic and the net, get stuck there and die. After considerable product research, my next try is the Hagen Marina multi-breeder. I can house 2 mothers separately in each breeder. I got 3. They arrived today. The babies supposedly drop through the grill in the bottom and join their friends in the fry tank. The mothers are safely kept inside the breeder. We'll see how it works. It's supposed to be good for both live bearers and egg layers. I'm experimenting with the live bearer functionality right now.